An optical method and system for generating calibration data are provided. The calibration data is for use in calibrating a part inspection system. The method includes supporting a calibration device having a central axis and a plurality of regions which are rotationally symmetric about the axis. The method further includes scanning the device with an array of spaced planes of radiation so that the device occludes each of the planes of radiation at spaced locations along the central axis to create a corresponding array of unobstructed planar portions of the planes of radiation. Each of the unobstructed planar portions contains an amount of radiation which is representative of a respective geometric dimension of the device. The method still further includes measuring the amount of radiation present in each of the unobstructed planar portions to obtain measurement signals. The method includes processing the measurement signals to obtain calibration data for calibrating the system. The calibration data is capable of converting raw data to calibrated data.